#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main() {
    string s1, s2;
    cin >> s1 >> s2;
    int n = s1.size(), m = s2.size();
    vector<vector<int>>dp(n + 1, vector<int>(m + 1));

    for (int i = 1; i <= n; i++) dp[i][0] = i;
    for (int j = 1; j <= m; j++) dp[0][j] = j;

    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (s1[i - 1] == s2[j - 1])
                dp[i][j] = dp[i - 1][j - 1];
            else
                dp[i][j] = min(dp[i - 1][j] + 1, min(dp[i][j - 1] + 1, dp[i - 1][j - 1] + 1));
        }
    }
    cout << dp[n][m] << endl;
    return 0;
}


